Aging Mars Rover Gets a Power Boost
Data from Spirit's power subsystem indicated that some dust blew off the rover's solar array on the following day, Sol 1812 (Feb. 6, 2009).
Credit: NASA/JPL-Caltech

NASA?s aging Mars rover Spirit has a bit more power under its hood thanks to some Martian winds that cleaned dust from its vital solar panels.

The handy cleaning occurred earlier this month and was discovered by engineers scanning data from Spirit?s power subsystem.

"We will be able to use this energy to do significantly more driving," said Colette Lohr, a rover mission manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "Our drives have been averaging about 50 minutes, and energy has usually been the limiting factor. We may be able to increase that to drives of an hour and a half."

The last time winds scoured Spirit?s solar array clean was in June 2007, but a massive dust storm on Mars later that year piled new grit atop the rover, mission managers said.

Thanks to the recent Martian winds, Spirit?s daily power levels rose to 240 watt-hours, an increase of about 30 watt-hours, mission managers said. For comparison, 30 watt-hours is the same amount of energy used by a 30-watt light bulb during one hour.

"It may not sound like a lot, but it is an important increase," said rover team engineer Jennifer Herman, who first discovered the power boost while studying data beamed home by Spirit on Feb. 6 - the rover?s 1,812 Martian day exploring the red planet.

Before the cleaning event, Spirit was generating about 210 watt-hours of power, with only 25 percent of the available sunlight penetrating the dust layer coating its top-mounted solar array. After the cleaning, the amount of sunlight getting through jumped to about 28 percent.

Spirit needs about 180 watt-hours just to survive on the Martian surface and maintain contact with its human handlers on Earth. The extra 30 watt-hours nearly doubles the amount of power the rover now has for driving across Mars or using its science instruments and robotic arm, mission managers said.

Spirit is currently rolling across a low, rocky plateau dubbed ?Home Plate,? which sits within the rover?s Gusev Crater landing site on Mars. Originally built for a planned 90-day mission, Spirit and its robotic twin Opportunity have now spent more than five years exploring their respective Martian landing sites on opposite sides of the planet.

Both Spirit and Opportunity have suffered some aches and pains associated with their unexpected longevity on the surface of Mars. Most recently, Spirit experienced an odd bout of amnesia when it failed to record and report a day of activities to flight controllers on Earth last month.

Spirit has since recovered from the glitch and driven about 30 feet (9 meters) after overcoming a stubborn rock that blocked its path in late January. Rover scientists hope to guide Spirit to the other side of its ?Home Plate? territory in the weeks to come.

On the other side of Mars, Spirit?s twin Opportunity is doggedly driving across the plains of its Meridiani Planum landing site as it heads towards a monster crater called Endeavour. Last week, Opportunity drove about 446 feet (nearly 136 meters) in one of a series of long hauls en route to the crater. The rover has visited a several craters, each larger than the last, in its more than five years of Mars exploration.

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